Conventional dehumidifiers known in the prior art include refrigerators equipped with compressors, refrigerant passages, etc., chemical desiccants, etc. although these apparatuses may work satisfactorily where they are installed appropriately for instruments, controlling, painting and other applicable uses, they have not been applied to such ordinary electric parts housing boxes that no fast-acting, absolute dehumidifying effect is required. With an aforementioned refrigerator, related capacity and cost do not meet at all. With a desiccant, a mass of the desiccant becomes considerably large for a long-term operation, regardless of the size of a housing box, etc., and in addition, maintenance may become laborious because of inspections for replacement timing and work.
With an electric parts housing box or the like, a simple moisture-proof, drip-proof structure is often incorporated, where a water-proof seal is installed at an opening/closing portion and a water-proof gland packing, etc. seals a bushing portion, instead of a dehumidifier using a refrigerator or a desiccant, and so on.
However, with such a moisture-proof, drip-proof structure as described above, once the concentration of moisture in the inside is higher than a limit, the structure may adversely affect dehumidifying, and even if the concentration of moisture in the atmosphere becomes lower than before, no dried state can be achieved, and in the extreme, dew may condense in the equipment, and if impurities contained in condensed dew make the equipment malfunction or break down the insulation, which is a fatal defect of a dehumidifier.
In these circumstances, an object of the present invention is to provide a novel dehumidifier free from the defects of a conventional dehumidifier known in the prior art, which can be used to dehumidify the interior of a hermetically sealed container or the like, with a moisture-proof, drip-proof structure, for a long time, basically without using electric power or a consumable chemical, while acting slowly using a simple, easy-operable construction.
Another object of the present invention is to offer such a dehumidifier as provided with low-cost auxiliary member materials that can support slow-acting dehumidifying, basically without using electric power or such a chemical or the like that must be replaced after the chemical is saturated with moisture.